Semiconductor wafer processing typically requires several stages of surface etching and layer depositing to form circuits. One device used to perform such etching and depositing is known as a downstream remote processor which comprises a water cooled aluminum housing surrounding a quartz waveguide. The waveguide comprises a length of a quartz tube passing through the aluminum container. The quartz tube has an open end exterior the container proximate a wafer which is to be processed.
A magnetron is attached to or positioned within the container to transmit microwaves throughout the container. The microwaves pass through the quartz and excite a reactive species which is introduced from external the container to the quartz tube. The microwaves cause the reactive species to be excited, forming radicals and free electrons which generate heat that is passed to the quartz tube. The heat, in conjunction with the radicals and the free electrons bombarding the quartz, causes the quartz to deteriorate. Deterioration results in small particles of the quartz tube being removed and carried with the radicals enroute to the silicon semiconductor wafer. Upon reaching the open end of the quartz tube, the plasma is directed onto a wafer for processing thereof.
Since small particles of quartz are carried with the radicals, some quartz is deposited on the surface of the wafer. The quartz particles then become contaminants which interfere with the circuitry being formed on the wafer. Additionally, the constant deterioration of the quartz tube results in the eventual destruction thereof requiring replacement. While quartz tubes are relatively inexpensive, the wafers being processed are not. Thus, there is a need for a method and apparatus to remove heat from the quartz tube to slow down the deterioration thereof and to lessen the likelihood of contamination of the wafer by the deposition of quartz particles.